JPS5970916A - Apparatus for measuring gas flow amount - Google Patents

Abstract

PURPOSE:To obtain an accurate gas flow amount within a short time, by a method wherein pulses of which intervals are changed corresponding to the gas flow amount are counted for a definite time and the obtained value is divided by a time elapsed before a new flow amount pulse is inputted. CONSTITUTION:The output pulses fp of a flow amount pulse generator 1 are counted by a counter 2 while the output pulses of an oscillator 31 are counted by a timer 3. When a predetermined time is elapsed, a signal TB1 is outputted from output O1. Thereafter, when a new flow amount pulse fp is inputted to the counter, the logical product of this signal and the signal TB1, that is, an output signal is generated in an AND gate 4. By the output of the AND gate 4, a division device 5 starts the performance of division wherein the flow amount pulse count value N to be devided is divided by a measuring time T being a divisor. The division result, that is, N/T is inputted to a latch 6 from the division device 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for measuring gas flow rate, and more particularly to a device for measuring gas flow rate per unit time.

Conventional Structure and Problems Conventionally, for example, a schematic make is well known as a device for measuring the integrated flow rate of gas. There are still some models of this model that have been modified for remote meter reading.

In this meter for remote meter reading, a magnet is installed in the link mechanism provided to use the diaphragm used in the meter or the reciprocating motion of the diaphragm as the opening/closing force of the on-off valve in the meter body. It is configured to convert into electric pulses using a magnetic sensor such as 1C, count these electric pulses with a counter, and display the output. In this type of application, it is not necessary to know the instantaneous value, it is only necessary to know how much volume of gas the user has consumed.
Such a so-called integration type gas flow rate measuring device is desired. Naturally, with this type of device, it is not possible to know the flow rate per unit time which is relatively short.

OBJECTS OF THE INVENTION The purpose of the invention is to measure gas flow rates with great accuracy.

Structure of the Invention This invention uses a counter to count pulses whose intervals change depending on the gas flow rate for a certain period of time (for example, 30 seconds).
By measuring how many pulses are present in a unit time (for example, one second) by division using a divider, the gas flow rate is accurately measured without errors due to variations in pulses.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The flow rate pulse generator 1 has a configuration similar to that used in the conventional device described above. For example, when a schematic meter is used as a flow rate detector, a magnet provided on a diaphragm or its link mechanism is combined with a magnetic field sensor. It becomes the composition. In this case, one pulse fp is generated each time the diaphragm moves back and forth.

When the diaphragm makes one reciprocation, a unit flow rate Qu flows, so a flow rate Qul flows at each pulse interval of the primitive pulse generator. The output pulse fp of the flow rate pulse generator 1 is used as an argument in the counter 2. On the other hand, counter 2
From the start of counting, timer 3 starts operating. The timer 3 is configured to count the output pulses of the oscillator 31 with a counter 32. When the counter 32 counts a predetermined number of pulses from the oscillator 31, that is, when a predetermined time Tφ, for example, one minute has elapsed, it outputs a signal TB1 from the output 01 (see FIG. 2).

After this, when a new flow rate pulse fP, that is, the Nth pulse in Fig. 2A, is input to the counter 2, this signal and
Logical product with the aforementioned signal TB1, that is, AND gate 4
An output signal is generated at (Figure 2...).

The output of the AND gate 4 causes the divider 6 to divide the counter 2
The content of the counter 32, that is, the flow rate pulse count value N, is used as the dividend, and the content of the counter 32, that is, the measurement time T is used as the divisor, and execution of division is started. The division result, that is, N/T is the divider 6
The signal is output from the latch 6 and input to the latch 6. Division result N/
T has the following physical meaning. Oscillator 31
The output accuracy is taken as a unit measurement time, and the flow rate per measurement time is expressed. Since the flow rate Qu flows at every pulse interval, the flow rate of (NXQuM) actually flowed during the open side time T. Therefore, if Qu = 1, the flow rate of the excavator 31 For example, if the output period is 1 second, the divider 5
The output is N /T (l /sea), which indicates the flow rate per unit time. Latch 6, AND
The input data, ie, the output of the divider 6, is latched with a pulse obtained by delaying the output of the gate 4 by the delay circuit 7 (FIG. 2, 2). On the other hand, at the output of the delay circuit 7, the counter 2
, 32, initialize both counters, and start the next measurement. Therefore, the Nth flow rate pulse fp
Once the first measurement is completed, the next measurement will begin. During the next measurement, the previous flow rate of lunch 6 is saved.

According to the embodiment described above, the flow rate per unit time (for example, 1 second) can be accurately determined in a relatively short measuring time (for example, about 1 minute). The measurement time is the time until a new flow pulse is generated after a predetermined time Tφ (for example, 1 minute) has elapsed, and the time for 78 flow pulses is calculated by the oscillator 31.
Since measurement can be performed with a resolution of the output frequency, high precision can be easily achieved by simply manipulating the output frequency of the oscillator 31 to obtain the desired measurement accuracy.

FIG. 3 shows another embodiment of the present invention to accommodate many types of gas meters. In a model gas meter, for example, the unit flow rate Qu from the diaphragm to the round trip is 0.6 l.
, 0,9 l, 1,7 l There are meters for the flow rate, and these quantities can be set using the unit flow rate setting device 8a.
, 8b, and 80. Use switch 9 to select the type of meter to which the flow rate pulse generator is attached. In the diagram,
Flow rate setting device 8b is selected, and its unit flow rate is 0.91
It is. The product of this value and the output of latch 6 is multiplier 1
Find it using 0. Its output is (N Xo, 9) l/
sec. The multiplication start signal of the multiplier 10 is a signal obtained by further delaying the output of the delay circuit 7 by a delay circuit 11. That is, after latching Qi and Q of latch 6, multiplication is started.

In addition to the circuit shown in Figure 1, a unit flow rate setting device 8 for each meter is added.
Provide a to 8C, select it appropriately with switch 9,
By calculating the product of the selected value and the output of the latch 6 using the multiplier 10, it is possible to correspond to a large number of meters.

Effects of the Invention As described in detail above, the present invention counts flow rate pulses with a counter and calculates the time T until a new flow rate pulse is input to the counter after a predetermined time has elapsed from the start of counting by the counter. The unit time is calculated by calculating the number N of flow pulses counted in this time T, and dividing the number N of flow pulses by the time T. You can know the flow rate.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an electric circuit of a gas flow rate measuring device according to an embodiment of the present invention, FIG. 2 is a timing diagram for explaining the operation of FIG. 1, and FIG. 3 is a diagram of an apparatus according to another embodiment of the present invention. FIG. 2 is a block diagram of an electric circuit. 1...Flow rate pulse generator, 2...Counter, 3...Timer, 6...Divider. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 79 - Figure 2 Figure 3 θα Continued from page 1 0 Inventor: Isao Homma, Tokyo Gas Co., Ltd., 1-2-16 Yaesu, Chuo-ku, Tokyo Applicant: Tokyo Gas Co., Ltd. Yaesu, Chuo-ku, Tokyo 1-2-16 1-chome No. 16 1985 6 ゛ Patent Application No. 180690 2 Name of the invention Gas flow rate measuring device 3 Person who corrects sleeves Relationship with the case q.1' Permission issued
Appointment Address 1006 Kadoma, Kadoma City, Osaka Name (582) Matsushita Electric Industrial Co., Ltd. Address
2, Matsushita Electric Industrial Co., Ltd., 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture, Claims: A flow rate sensor is provided in the gas supply line, and a flow rate pulse is output as a signal according to the gas flow rate.The pulse is counted by a counter. , the gas flow rate is measured by the timer of this counter, divided by a divider which takes the output of the counter as the dividend input and the output of the timer as the divisor input, and uses the output of the divider as the flow rate signal and output signal. measuring device.

Claims (1)

[Claims] a flow rate pulse generator that outputs electrical pulses in accordance with the gas flow rate; a counter that counts the flow rate pulses; and a new flow rate pulse that is input to the counter after a predetermined period of time has elapsed from the start of counting by the counter. A gas flow rate measuring device comprising: a timer for measuring the time until the end; a divider using the counter output as the dividend input and the timer output as the divisor input, and using the divider output as an output signal as a flow rate signal. .